Reversible moldboard and disc type plows have been used for some time. They require an implement support which is shiftable to change the angle at which the implement is pulled through the earth as it proceeds back and forth so that the angle for one direction is the same as that for the following opposite direction.
A reversible plow throws the dirt in the same direction when travelling in opposite directions in a longitudinal path. The need for such a plow arises from the necessity to create equal furrows without leaving free spaces and to provide an even, levelled surface.